1. Field of the Invention
This invention relates to an obstacle avoiding apparatus, an obstacle avoiding method, an obstacle avoiding program and a mobile robot apparatus that plan a moving route on the basis of an obstacle environment map prepared by acquiring information in the environment and avoid obstacles.
2. Description of the Related Art
Unlike industrial robots, autonomous type robot apparatus can autonomously move according to the conditions of the surrounding and the internal conditions of the robot apparatus itself. For example, such a robot apparatus can detect external obstacles and autonomously move by planning a moving route that avoids the obstacles.
Path finding studies have been conducted for long as typical studies of artificial intelligence along with problems of computational geometry such as traveling salesman problem and interference check. Path finding for a floating object in a known environment such as the so-called piano mover's problem of geometrically determining the route along which a piano is moved out from a small room having an intricate geometry may be a typical problem. Many techniques have been proposed for benchmark problems for the efficiency of computational geometry and search algorithms have been proposed in this field of study.
For example, Patent Document 1 [Jpn. Pat. Appln. Laid-Open Publication No. 2003-266345] proposes a path finding technique for avoiding obstacles for a biped robot apparatus. According to the Patent Document 1, a moving route is planned for a robot apparatus so as not to interfere with obstacles by modeling the robot apparatus by means of cylinders and using an occupancy grid that shows the profiles of obstacles as obstacle environment map.
When planning a route for getting to goal G from current position R of a robot apparatus, for instance, firstly an obstacle environment map is prepared as illustrated in FIG. 1A. The obstacle environment map shows the obstacles found within the space on the floor where the robot apparatus is expected to move from the floor level to the height of a cylinder 301 formed by modeling the robot apparatus and also the holes cut down from the floor. In FIG. 1A, the black cells indicate the regions occupied by obstacles and the white cells indicate the regions where the robot apparatus can move freely. Then, the robot apparatus is made equivalent to the contracted one at the current position R as shown in FIG. 1B by enlarging the regions occupied by obstacles in the environment map of FIG. 1A by the half diameter of the cylinder 301. Thus, it is possible to check the interferences of the robot apparatus with the obstacles that can take place by checking the overlaps of the model and the enlarged obstacle regions. As a result, it is possible to plan routes that avoid obstacles as indicated by arrows in FIG. 1B by means of a technique called A* search.